Sports injuries are a serious problem. In football, for example, torn anterior cruciate (ACL) knee ligaments are common. The ACL is one of four ligaments that stabilize the knee and prevents excessive or abnormal range of motion. Football, due to its high impact and high contact movements, makes it one of the most common sports with ACL sprains and tears. Concussions are also a major problem in football. More than 100 lawsuits have been filed and settled against the National Football League (NFL) by players claiming that the NFL did not do enough to inform and protect them from the brain injuries caused by repeated blows to the players' heads. While the NFL has an unwavering commitment to player health and making the game safer at all levels, protective equipment still remains a challenge. When it comes to concussions, football helmet safety has made little progress over the past decades. A team of Ohio researchers from Cleveland Clinic's Spine Research Laboratory and Case Reserve University tested eleven commonly used modern polycarbonate helmets and two early 20th century “leatherhead” helmets. Using the same testing as the National Operating Committee on Standards for Athletic Equipment (NOCSAE), the researchers found the old and new helmets performed equally. In some impacts, the leather helmets performed better. Serious sports injuries are hardly limited to football, though. It is well documented that injuries are also a serious problem in other sports, such as bicycling, soccer, baseball, hockey, basketball etc.
A sizable industry has developed to try to protect players from the type of injuries commonly caused by their sports. In football, for example, players are required to wear helmets to protect their heads from concussion. These helmets generally consist of a softer, dense inner layer, such as polyurethane foam or vinyl foam, placed next the player's head and a hard exterior polymer shell, such as polycarbonate. Inflatable bladders have also been used for some soft inner layers of football helmets. Examples of inflatable bladders for helmets are provided in Sheridan's U.S. Pat. No. 6,418,564, Fitzpatrick's U.S. Pat. No. 5,039,035, Anderson's U.S. Patent Application Publication No. 2012/0102630 and Moore's U.S. Patent Application Publication No. 2006/0101550. Metal or plastic rods are then attached to the helmet to protect the player's face, while still allowing the player to see the game.
Despite years of work to try to perfect helmet technology for football and other sports, concussions remain a serious problem. The CDC estimates that as many as three million, eight hundred thousand sports-related concussions occur in the U.S. each year. Concussions happen deep in the brain's white matter when forces transmitted from a big impact strain nerve cells and their connections, the axons. Different types of forces are involved in blows or impacts to a body. Impacts can have both linear and rotational forces. As illustrated in FIG. 1A, the linear force is a straight-line force directed at the body part's center of gravity. By comparison, as shown in FIG. 1B, the rotational force occurs most acutely during angular impacts where the force is not directed at the body part's center of gravity. As illustrated in FIG. 1C, the rotational impact force typically has a linear component and a glancing, tangential component. Research shows that the brain only needs to move a little bit when struck, just millimeters, to cause a concussion. Yet no helmets have been produced to optimally absorb, dampen and protect against the few millimeters of brain motion that causes the damage. It appears that commercial sports helmets made from hard or stiff foams result in hard landings.
The boldest safety claim from mainstream football helmet makers comes from Riddell. Riddell's “360” helmet builds upon a system called “Concussion Reducing Technology” (CRT) which, in essence, only adds more padding. The attempt by Riddell was to use hinge clips on the sides and face mask to disperse frontal impacts. It also uses a hexagonal liner system of foam and an inflatable back, neck and side. Another approach by Peter Hallidin, a biomechanical engineer at the Royal Institute of Technology in Stockholm, Sweden is a “Multidirectional Impact Protection System” (MIPS), which is also the name of a company he co-founded. The idea of MIPS is to fit a plastic layer snugly on a head beneath the padding in a helmet. By allowing the head to float during an impact, MIPS can dampen some of the rotational force before it makes its way to the brain. The plastic layer, though, will obviously not allow keeping the head cool. The Bicycle Helmet Safety Institute (“BHSI”) lists “Ten Principles for the Ideal Helmet” and concludes no one makes such a helmet. The number one priority on the wish list is a helmet that will manage as much energy as possible and obtain a soft landing. BSHI reveals that the lab tests for helmet standards are pass/fail tests and, as such, are not designed to show “softer landing” protection possibilities. Moreover, legal worries prevent companies from advertising anything about impact performance beyond meeting the standard, a point that can be defended in court even if the user is injured.
Over four million, two hundred thousand persons in the United States will suit up and play football each year. Most of them are children with still developing brains. Many more millions will ride bikes and play all other types of sports. Every one of them needs more optimal protection of head, knees and other body parts.